It is important to examine the philosophical and religious foundations
of the Vajrayana so as to better understand how it fits into the Buddhist tradition as a
whole. As we look at the Vajrayana tradition in more detail, we will find that it
incorporates a number of important Mahayana ideas. Three religious and philosophical ideas
that are prevalent in the Mahayana play a vital role in the Vajrayana as well. These are
the ideas of (1) emptiness, (2) Mind Only, and (3) expedient or skillful means.

In Chapter 22, I had occasion to refer to the fact that the Tibetan
tradition regards Nagarjuna and Asanga as the founders of the Vajrayana path. In addition
to the Vajrayana elements contained in their biographies, as discussed in Chapter 22,
there is an equally significant way Nagarjuna and Asanga can be considered Vajrayana's
founding fathers--namely, because of their advocacy and explanation of the ideas of
emptiness and the primacy of consciousness (or Mind Only). A number of Vajrayana works in
the Tibetan canon are attributed to Nagarjuna and Asanga, though this attribution is
disputed by modern scholars. Whether or not Nagarjuna and Asanga actually wrote
specifically Vajrayana works, it is quite clear that, without the ideas they put forward,
the Vajrayana would be unintelligible, and very likely impossible as well.

Let us look first at the idea of emptiness, which is so characteristic
of the writings of Nagarjuna. In Chapter 22, I referred to a situation in which Nagarjuna
is said to have transformed base objects into gold. This can be seen as a metaphor for the
main project with which the Vajrayana is concerned: transforming common experience into
the experience of enlightenment. If we look at this analogy of alchemy, we see that, for
transformation to be possible, the base object cannot have any real, permanent nature of
its own. For instance, if a piece of coal were to have an unchanging, intrinsic nature, it
could never be changed into anything else. Yet we know that a piece of coal can, under
certain conditions, become a diamond.

The idea of an unchanging, independent character is expressed in
Sanskrit by the term svabhava, which means 'own-being' or 'self-existence.' The absence of
own-being is nihsvabhava, which is synonymous with emptiness. Emptiness is, of course, not
nothingness. It is, rather, a kind of openness, a situation in which phenomena exist
dependent on causes and conditions.

Although this idea of emptiness is most commonly associated with
Nagarjuna and the Middle Way school, like the other important doctrines of the Mahayana,
it also exists in the Theravada tradition. For example, according to the Theravada canon,
the Buddha likened all phenomena to the flame of an oil lamp, which exists dependent on
the oil and the wick. The flame is nothing in itself. Similarly, all phenomena depend on
causes and conditions.

In the Mahayana, where this idea is elaborated at great length, all
phenomena are likened to a magical illusion. An illusory elephant, for example, appears
dependent on some basis, like a hill of earth or a piece of wood, and is brought into
being by a magician using certain magical spells and so forth. Thus illusory appearances
come about dependent on certain causes and conditions. Similarly, all phenomena exist
dependent on certain causes and conditions. It is because of this dependence, this
emptiness, that transformation is possible.

Nagarjuna says that if there were any own-being, transformation by
means of the path of liberation would be impossible. In other words, if that lump of coal
we referred to a moment ago had an unchangeable nature, it could never become a diamond.
Similarly, if each and every one of us had an own-being or permanent existence as
ordinary, afflicted sentient beings--if this were our identity--then no matter how much we
practiced the Dharma, we could never become enlightened. It is because we are subject to
the afflictions (ignorance, attachment, and aversion) that we have the nature of ordinary
sentient beings. But if we replace ignorance with wisdom, attachment with lack of
attachment, and aversion with love and compassion, we can change these conditions. By
changing these conditions, we can change the nature of our being and become Buddhas.
Emptiness is therefore absolutely necessary to allow for transformation from the condition
of samsara to the liberation of nirvana.

Let us look now at the second idea, that of the role of the mind in
experience. Here Asanga and his younger brother Vasubandhu made two general points: (a)
that objects have no stable or fixed form of appearance, and (b) that objects appear even
without an external stimulus.

Like other major tenets of the Mahayana and Vajrayana, these two points
are not absent from the Theravada tradition. The first is evident in a number of Buddhist
texts. For example, the incident involving the Elder Tissa is well known within Theravada
circles: when asked whether he had seen a woman on the road, Tissa replied that he did not
know whether it was a man or a woman, but only that he had seen a heap of bones going up
the road. This shows that objects have no stable or fixed form of appearance; what appears
as an attractive woman to one man appears as a heap of bones to another.

The Mahayana tradition elaborates on this by recourse to the experience
of a number of altered states of consciousness. For example, one feels the earth move, or
that one has enormous power, when one has imbibed too much alcohol. Similarly, under the
influence of psychedelic substances, one's perception of objects is different. In his
Twenty Verses on Cognition Only, Vasubandhu illustrates this with reference to the
experience of the beings of the six realms (see also Chapter 19). There, he spells out the
diverse ways objects appear depending on the subjective conditions of the perceiver,
concluding that objects appear in different shapes and forms to different sentient beings
according to their karmic condition.

The second point, that objects appear even without an external
stimulus, is also found in the early Theravada tradition. For example, in Buddhaghosha's
explanation of the three stages of concentration (preliminary, proximate, and
accomplished), the image of meditation becomes internalized at the proximate stage. If a
meditator uses, say, a blue disk at the first stage, at the second stage that disk becomes
internalized and he now meditates on a mental replica of it. Consequently, whereas on the
first stage he uses a physical object as his object of meditation, on the second stage of
concentration he no longer needs that external support. The object now appears to him
without the need of an external stimulus. We can also see this in dreams, where the
dreamer experiences objects without any external stimuli.

Vasubandhu adds to this the case of the wardens of the hell realms. If
these wardens were reborn in the hells because of their own karma, they, too, would
experience the sufferings there. But since wardens are in the hells simply to torment hell
beings, Vasubandhu suggests that they are mere creations of the minds of the hell beings
themselves. In other words, because of their unwholesome karma, hell beings project images
of wardens who then proceed to torment them.

In all these cases--the experiences of meditation, of dreaming, and of
hell beings--objects appear without any external stimulus. This is why it is said that,
just as a painter might paint a portrait of the demon and then be terrified by it, so
unenlightened beings paint a picture of the six realms of samsara and then are tormented
and terrified by that picture. Through the power of our minds, we create the six realms of
existence and then circle in them endlessly. We are able to create these six realms
precisely because there is no own-being.

These first two ideas--the idea of emptiness and the idea of the role
of the mind in creating experience--go together. Objects have no independent existence.
Their existence is relative to causes and conditions--most importantly, the mental causes
and conditions of ignorance, attachment, aversion, greed, anger, jealousy, and the like.
Because of these mental conditions, and because of the fact that phenomena are empty, the
mind constructs and creates experience in a particular form, in the form of the suffering
of the six realms.

Just as the mind can work unconsciously and automatically to create the
experience of suffering in the six realms, so the mind can be made to work deliberately
and consciously to bring about a change in that experience, to bring about the experience
of liberation. This is quite clear in the example of the experience of meditation that we
considered a moment ago. Ordinarily, the mind functions unconsciously and automatically to
create experience. We respond to an object, such as the form of a woman, because of our
habitual conditioning, because we are subject to desire and ignorance. In meditation we
train the mind to function in a chosen, decisive way to change our experience. Through the
experience of meditation, we can change our perception of the object in the same way the
Elder Tissa changed his perception so that he was able to see the form of a woman as only
a heap of bones.

Again, we ordinarily perceive different colors automatically, in an
undirected and unspecified way. Through meditation, we can alter that situation so that we
can, at will, visualize and create a particular patch of color within our mental
experience. The idea of emptiness and the idea of the creative power of the mind are
clearly present in the structure of the Vajrayana techniques of meditation, which we will
be looking at in greater detail in Chapter 29. Emptiness and the creative power of the
mind together give us the ability and the methodology needed to transform our experience.
We can transform our experience because nothing has any nature of its own, and the way we
transform it is through using the power of our minds to create and determine the way we
experience objects.

As mentioned in Chapter 22, the Vajrayana is one with the Mahayana both
in its starting point and in its goal. The fundamental idea in the Mahayana tradition is
the enlightenment thought or mind (bodhichitta, the resolve to achieve enlightenment for
the sake of all sentient beings), and the fruit of this resolve is the attainment of
Buddhahood, with its transcendental dimension and its phenomenal dimension. The phenomenal
dimension is an expression of the Buddha's great compassion, which manifests itself in
skillful means--the third idea prevalent in the Mahayana and crucial to the Vajrayana as
well.

Skillful means is the ability to reach all sentient beings at their own
levels. In many Mahayana sutras, this is explained with the help of analogies, such as the
parable of the three carts and that of rainfall and the light of the sun and moon in the
Lotus Sutra (see Chapter 15) The phenomenal dimension of the Buddha appears to all
sentient beings according to their particular needs and abilities. It manifests itself in
a variety of forms, such as that of the beautiful maiden whom the Buddha caused to appear
for the sake of Kshema (see Chapter 22). In many Mahayana discourses and treatises, the
Buddha manifests himself in the form of ordinary people or gods in order to assist
sentient beings along the path to liberation.

It is in this way, too, that the Buddha manifests himself in the
special forms of the deities of the Vajrayana pantheon according to the needs and
propensities of sentient beings. For example, in the case of the five celestial Buddhas,
the Buddha manifests himself in five special forms that correspond to the particular
karmic propensities of sentient beings. Thus he manifests as the Buddha Vairochana
especially for sentient beings whose primary affliction is ignorance, while it is
Akshobhya who appears to those whose primary affliction is ill-will and Amitabha to those
whose primary affliction is attachment. The Buddha manifests himself in these different
forms to best assist different sentient beings with particular karmic problems.

These manifestations of the Buddha interact with sentient beings to
bring about their liberation. There is a kind of interdependence between the
manifestations of the Buddha (in the forms of the Heavenly Buddhas and of deities of the
Vajrayana pantheon) and the development of sentient beings through the practice of
meditation. To illustrate this, let me return to the story of Asanga and the future Buddha
Maitreya. Asanga meditated for twelve years before he was able to perceive Maitreya.
Maitreya was with him all along, but Asanga had to develop his vision so that he was in a
position to experience Maitreya directly. In the same way, the manifestations of the
Buddha are around us all the time, but to perceive them directly we must develop our minds
through meditation, through the careful purification of our beings. This purification of
the mind may be likened to the process of tuning a television set to receive a particular
transmission. The transmission is there all along, but unless and until the receiver is
tuned to the correct frequency to receive it, the picture cannot be seen.

If we remember these three principles--the principle of emptiness, the
principle of the power of the mind to determine the nature of our experience, and the
principle of skillful means, we will be able to understand how the Vajrayana path can
work. We will also be able to understand the diversity of the forms and images that the
Vajrayana uses to expedite the process of transformation.